Sydney weather: rain makes for wet trip home

Peter Hannam

Sydney commuters can expect another soggy journey home as the remnants of an east coast low continue to soak coastal regions of the state.

This city's rainfall this month has topped 180 millimetres, making it the wettest August since 1998 and more than double the long-run average, according to Bureau of Meteorology senior climatologist Agata Imielska.

Another 3-10 millimetres is expected on Wednesday after another mild night, with temperatures likely to drop to 13 degrees. Cloudy skies and scattered showers will keep the maximum to 17 degrees, the bureau said.

"There'll be a few showers around on Wednesday but not nearly as many as today," Weatherzone meteorologist Rob Sharpe said. "Sydney will see some drying out, particularly over the weekend."

A bride and groom look for the bright side in the Sydney Botanic Garden. Photo: Wolter Peeters

National view

Sydney and NSW coastal regions have been soaked by east coast lows in recent weeks, ending a generally dry spell for much of the state.

So far this year, Sydney has had just under 600 millimetres of rain, well shy of the long-run average of 908.6 millimetres for the first eight months of the year.

Those dry conditions have generally shifted south as large, slow-moving high pressure systems have dominated.

Hobart, for instance, clocked up its 15th consecutive day without measurable rain on Tuesday. With only a low chance of rain forecast for much of the next week, the city is likely to smash the previous longest stretch of rainless days of 16 set in 1949, according to bureau manager of climate prediction services Andrew Watkins.

Perth, meanwhile, has had average maximums this month running almost three degrees above normal for August.

El Nino watch

Those warmer, drier conditions indicate that El Nino-like conditions remain influential over much of Australia.

According to the Bureau of Meteorology's latest El Nino update, the chances of such an event this year remain greater than 50 per cent.

A weakening earlier in August of the easterly trade winds, a key signal of an impending El Nino, had failed to reinforce the warming of sea-surface temperatures needed to get an event under way, the bureau said in its latest update.

However, sea temperatures about 100-150 metres below the surface in the central and western equatorial regions are showing renewed warming – to be 1.5-2 degrees above normal – a trend that could see conditions again tilt in favour of an El Nino.

"We're back starting the process again, to some degree," Dr Watkins said. "We're certainly not out of the woods yet."

Meteorologists have been studying conditions in the Pacific to see strong signals of an El Nino seem earlier this year take hold.

Such events tend to bring drier and hotter than usual conditions to Australia and large parts of Asia, while regions on the eastern Pacific get much more rain than normal – a result drought-hit California would like to see.

Four of the seven climate models surveyed by the bureau point to an El Nino event by the coming 2014-15 austral summer, and some El Nino-like weather patterns are already evident, Dr Watkins said.

These include a delayed sub-continent monsoon affecting India's harvests and those warmer and drier than usual conditions across southern Australia – even if Sydney has lately been wet.